Brush-holder.



-- A. J. BROWN.

BRUSH HOLDER;

APPLICATION FILED JULY 30, 1906.

Patented Apr. 6, 1909.

Fiq. 2

Fig.1

/N VE N TOR ArThur J. Brown BY WITNESSES CAD , P TO I? or ARTHUR J'. BROWN, OF NORWOOD, OHIO, ASSIGNOR TO ALLlS-CHALMERS COMPANY, A COR- PORATION OF NEW JERSEY, AND THE BULLOCK ELECTRIC MANUFACTURING COMPANY,

A CORPORATION OF OHIO.

BRUSHJ-IOLDER.

Specification of Letters -fatent.

Patented April 6, 1909.

Application filed July 30, 1908. Serial No. 328,329.

T 0 all whom it may concern:

Be it known that I, ARTHUR J. BROWN, a citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Brush Holders, of which the following is a full, clear, and exact specification.

My invention relates to brush-holders for dynamoelectric machines.

In a well known type of brush-holder the brush slides toward or away from the commutator in a guide or socket, and is pressed tow rd the commutator, generally, by a pressure finger, one end of which bears on the brush, and the other end of which is pivoted to the brush-holder. Usually a long spiral spring, connected at one end to the finger and at the other end to the stationary frame or casting, is employed to press the finger yieldingly onto the top of the brush. l l ith this construction, the spring is ll'ldCll more distended when the brush is long than when the brush has been shortened by wear. The result is that unless the effective lever arm for the spring is increased as the brush wears away, the pressure of the brush. on the commutator is not uniform during the life of the brush, being greater when the brush is long than when it is short. Furthermore the direction in which the press is a i plied to the brush depends on the position of the arm and hence on the length of the brush. If the pressureis applied in the direction of movement of the brush, the brush slides easily and uniformly in the socket. if, however, as is usually the case, the pressure is applied in some other direction so that only a component of the pressure is in. line with the movemerit of the brush, the latter is pressed against the sides of the socket causing it to stick or move unevenly.

One of the objects of my invention is to provide means whereby the pressure on the brush can be maintained substantially uniform for all lengths of the brush.

A further object is to provide means whereby the pressure is applied to the brush at all times substantially in the line of movement of the latter, so that the brush moves in the brush socket easily and without sticking.

In carrying out my invention I provide at the end of the pressure device an adjustable member which engages the brush, the position of which member can be adjusted as the brush wears away so that the pressure device can be maintained in substantially the same position, regardless of the length of the brush.

lore specifically considered, my invention consists in a brush-holder having a brush guide or socket, and a pivoted spring-pressed linger having at its outer free end, a screw or bolt the position of which may be adjusted to maintain the pressure iinger in the proper position for different lengths of the brush.

For a better understanding of my invention, reference is had to the accompanying drawings in which Figure 1 is a side elevation of a brushholder equipped with my invention, parts being broken away and in section; Fig. 2 is an end view of the same; Fig. 3 is a side elevation of modification; and 4 is an end view of the same.

Referring now to the figures of the drawing in which have shown the best forms of my invention now lznown to me, 10 represents a brush stud on ich is secured by means of a set screw 11, r etal brush-holder frame or casting l2 havi g at one end a brush guide or socket 13 which receives the brush l l adapted to be fed inward toward the corn mutator or other contact surface as the brush wears The brush is pressed toward the ron'unutator by a pressure device, which is in this case a n-essurc linger 16 having a transverse pivotal member 17 mounted in the of the brush frame. AtlS is shown a long spiral spring, one end of which is adapted to be adjustably secured to the pressure finger in one of several notches 19, and the other end of which is secured to a pin 20 in the lower end of the brush fran'ie.

it is seen that as the brush wears away and the pressure linger moves toward the coin- .nutator that the spiral. spring 18 contracts consider b nd hence the pressure on the brush (loci cos as the brush wears away.

Furthe lore if the brush finger is above a line d1 ,evn suhst ntially from the pivotal center 17 at right angles to the line of movement of the brush, 1 *essure is applied to the brush not in its direction of movement but at an angle thereto, ich. pressure tends to force the brush toward the outer guiding surface, 1d if the pressure finger is below a line drawn from th pivotal center 17 right angles to the line of movement of the brush, the brush is pressed toward the inner guiding surface of the socket. In either case, the

brush tends to stick in the socket, and may have an uneven or non-uniform movement. To avoid these diiiiculties I provide on the end of the pressure finger which bears on the brush, an adjustable member, in this case i provide screw-threaded members adapted to move toward or away from the rush as is desired. in Figs. 1 and 2, i screw 20 mounted in the end of the pressure finger, adapted to move substantially right angles to the finger. The iower end of the screw 20 hears upon the brush and the upper end is provided with a knurled head 21 by means of which the position of the screw can be adjusted. The screw is prevented from being accidentally moved by cheeknut 22. As shown in the drawing, the linger is in position for transmitting the pressure of the spring in the proper direction, and in order that the brush may he held on the commutator with uniform pressure, the finger must be maintained in this position and the screw 20 adjusted toward the bru h as the latter is shortened by wear.

In Figs. 3 and a i have shown a slight modification of my invention. in this ease t end of the pressure finger 16 is slotted as shown at 23 to receive a knurled thumb-nut 2d. Passing through the thmnb-nut, and threaded therein, is a movable screw 25, the latter passing freely through the end of the pressure linger, thus by turning the thumhnut 2d the screw is moved toward or from the brush, and as the brush wears .y, the pressure finger ean be maintained in the proper position.

It is evident that many modifications can have shown a 1 brush, wh

he made without departing from the spirit and scope of my invention, and I therefore do not wish to be confined to the exact details shown.

i hat I claim as new and desire to secure by Letters Patent is 2* 1. In combination, a brush holder having a hru h guide or socket, a brush therein, and a spring actuated pressure finger pivoted at one end to the holder and having an member iv sure can be exerted upon LI of movement thereof, regar less of the length of said brush.

2. in combination, a brush holder having a brush guide or socket, a brush adapted to slide in said guide or socket, and a spring actuated pressure finger pivoted at one end to the holder and having an out .1 free end provided with an opening or passageway, a threaded member of considerahle length in said opening or passage; ay and hearing on the end of the brush nd means whereltiy said mend) may h h .isted in the direction of movement or brush whcrehy uniform pressure ma be exerted on the brush in the same lengths of the rush.

tes 'niony wh -r direction for different 

